1. Field of the Invention
This invention relates generally to bicycle brake lever assemblies. It relates more specifically to a bicycle brake lever assembly of the type which includes a mount bracket elongated enough to work as a palm rest for a rider.
2. Description of the Prior Art
As is well known, many of sports bicycles such as racing bicycles are provided with a drop type handlebar which includes an intermediate straight portion centrally connected to a handlebar stem by means of a handlebar lug, and a pair of U-shaped, downwardly bent side portions (drop portions) formed at both ends of the intermediate straight portion. In such a handlebar, a brake lever assembly is mounted to each drop portion to enable the rider to conduct a braking operation while he (or she) grips the drop portion in a high speed running posture.
Generally, a brake lever assembly for such a sports bicycle comprises a mount bracket fixed to each handlebar drop portion to extend forward therefrom, and a brake lever pivotally connected to the mount bracket to extend downward therefrom. A brake control cable connected to a corresponding brake assembly is usually introduced from above into the mount bracket for connection to the brake lever, as disclosed for example in U.S. Pat. Nos. 3,403,577, 3,546,960, 3,974,712, 4,267,746, 4,679,460. Alternatively, the control cable may be guided from behind into the mount bracket, as disclosed for example in U.S. Pat. Nos. 4,425,819 or 4,459,871.
In running, the rider tries to assume an optimum riding posture depending on various purposes and road conditions. For example, when running at a high speed on a flat road or downhill, the rider normally grips the drop portions of the handlebar, thereby assuming a forwardly inclined riding posture. On the other hand, a more relaxing riding posture is required when running at a low speed on an uphill for example. One good gripping position for such running is the mount bracket of the brake lever assembly because the rider's hand can still be held close to the brake lever for braking.
For this purpose, the mount bracket of the brake lever assembly is often made to have an elongated upper surface, preferably in the shape of a saddle, for working as a palm rest. Further, the mount bracket may be formed at a front end portion thereof with an integral hand stopper which projects upward from the palm resting upper surface for preventing the rider's hand from forwardly slipping off the mount bracket due to an inertial force produced when braking.
In general, a typical brake lever assembly to be mounted to the drop type handlebar is designed to be most conveniently operated when the rider assumes the forwardly inclined posture by gripping each drop portion of the handlebar. In fact, such a design is preferred because the forwardly inclined posture is usually taken when running at a high speed, so that most effective braking is required for this running posture. Thus, the brake lever of the typical brake lever assembly is made to extend downward away from the mount bracket generally along the curvature of the handlebar drop portion.
However, the typical design for the brake lever assembly is disadvantageous for conducting a braking operation while gripping the mount bracket. Specifically, the brake lever extends downward away from the mount bracket, so that the rider's fingers, when extended in a natural fashion with the palm resting on the upper surface of the mount bracket, become substantially parallel to the brake lever. Such a finger orientation is very inconvenient for operating the brake lever. Therefore, selected fingers (usually the forefinger and middle finger) of the rider must be unnaturally oriented to engage the brake lever the pivotal point thereof and pull it rearwardly toward the handlebar drop portion. Obviously, combined with a small lever ratio, such an unnatural operation will not result in a sufficient braking force.
Further, while resting or gripping on the mount bracket, the rider must pull the brake lever toward the handlebar drop portion. Such a braking operation generates a reaction force which causes the rider's hand to slip forward on the palm resting upper surface of the mount bracket. Though the hand stopper provided at the front end of the mount bracket is effective for preventing the rider's hand from forwardly slipping off the mount bracket, the operational reaction force at least gives the rider an anxiety of complete slip-off. This anxiety becomes more realistic due to the fact that a forward inertial force is produced at the time of braking.
A similar problem also occurs when the brake lever assembly is mounted to a bull-horn type handlebar which is increasingly used for racing bicycles. This type of handlebar comprises a substantially horizontal intermediate portion, and a pair of curved side portions (bull horns) which extend forwardly upward from both ends of the intermediate portions like bull horns. The brake lever assembly, which is substantially identical in arrangement to the one for a drop type handlebar, is mounted to each horn tip of the bull-horn handlebar.